Re-built servo failures/warranty

[0neoffive]

FYI: Having rescued more than 300 of the Girling treasures (MK 2A mostly), I have seen any number of post re-build failures. The most recent cause of failure seems to be impatience. Almost a dozen have come back this year with jamming contaminations from the returning fluids. It seems that everyone is religious about flushing the master cylinder thru to the input line and making sure the fresh fluid fills the servo. But, a fresh servo boost loosens all that down stream nasty stuff inside the "out" lines and it washes back to cram the rear portions of the control & power valves to the point that it will all stop working. Take the time to completely flush those lines until clear guys & gals.

 

[Orig65Tiger]

I just completed a rebuild of all brake components. Since the system was filled with silicone fluid and I want to return to conventional fluid, I flushed all lines with denatured alcohol while they were open. I will use conventional brake fluid when I refill and bleed the system.

The only piece I did not rebuild was my servo. Mine is a 7" with the crimp canister and the only rebuild kit I am aware of is from Britain and very pricey. Since the booster was operating properly and showed no sign of fluid in the vacuum line or the canister, I chose to leave it alone. So far I have simply let the silicone fluid leak out of the booster.

Question: What is the correct way to bench bleed the booster before I put it back in the car? It's the only place where I may still have residual silicone fluid. I have a Phoenix injector brake bleeder which allows me to pressure bleed on the bench in either direction of fluid flow. What's the best way?

Thank you

 

[0neoffive]

MK2 B servo bleed

Actually, gravity will do 90% of the job for you. The internal design is such that you can place the unit with the line connection bosses facing mother earth and a slight rocking motion or air blast in the connections will clear them fairly well. If you want to inject a bit of fluid first to dilute and clear the valve body, use the "IN" boss. Yup; it can be messy, but effective.

 

[Orig65Tiger]

Exactly what I wanted to know. I'm never sure whether there might be a trick to getting rid of trapped fluids in the various brake components.

Jim